[dotnet] add defined method to Mu

add substr Ops and substr method to a barebones Match class
oh, and, the rest of the initial accessors implementation
added 56-accessors.t - basic tests of accessors & (fluent) mutators

common/NQP/NQPSetting.pm

@@ -408,6 +408,10 @@ sub die($message) {
     nqp::throw_dynamic(NQPException.new($message), 0)
 }
 
+sub substr(NQPStr $str, NQPInt $offset, NQPInt $length?) {
+    nqp::substr($str, $offset, $length)
+}
+
 # For tests.
 my $count := NQPInt.new();
 sub plan($n) {
@@ -553,7 +557,8 @@ my knowhow NQPClassHOW {
         # Publish type cache.
         self.publish_type_cache($obj);
 
-        # XXX TODO: Compose attributes.
+        # Compose attributes.
+        for @!attributes { $_.compose($obj) }
 
         $obj
     }
@@ -698,7 +703,7 @@ my knowhow NQPClassHOW {
         while $i != $mro_length {
             my %meths := @!mro[$i].HOW.method_table($obj);
             my $found := %meths{$name};
-            if $found.defined {
+            if nqp::repr_defined($found) {
                 return $found;
             }
             $i := $i + 1;
@@ -710,17 +715,46 @@ my knowhow NQPClassHOW {
 # A simple attribute meta-object.
 my knowhow NQPAttribute {
     has $!name;
-    method new(:$name) {
-        my $obj := nqp::instance_of(self);
-        $obj.BUILD(:name($name));
+    has $!has_accessor;
+    has $!has_mutator;
+    method new(:$name, :$has_accessor, :$has_mutator) {
+        my $obj := nqp::instance_of(self.WHAT);
+        $obj.BUILD(:name($name), :has_accessor($has_accessor),
+            :has_mutator($has_mutator));
         $obj
     }
-    method BUILD(:$name) {
-        $!name := $name
+
+    method BUILD(:$name, :$has_accessor, :$has_mutator) {
+        $!name := $name;
+        $!has_accessor := $has_accessor;
+        $!has_mutator := $has_mutator;
     }
     method name() {
         $!name
     }
+    method has_accessor() {
+        $!has_accessor
+    }
+    method has_mutator() {
+        $!has_mutator
+    }
+    method compose($obj) {
+        my $long_name := $!name;
+        my $short_name := nqp::substr($!name, 2);
+        if $!has_accessor {
+            if $!has_mutator {
+                $obj.HOW.add_method($obj, $short_name, method ($val?) {
+                    return nqp::repr_defined($val)
+                        ?? nqp::bind_attr(self, $obj.WHAT, $long_name, $val)
+                        !! nqp::get_attr(self, $obj.WHAT, $long_name);
+                });
+            } else {
+                $obj.HOW.add_method($obj, nqp::substr($short_name, 2), method () {
+                    nqp::get_attr(self, $obj.WHAT, $long_name);
+                });
+            }
+        }
+    }
 }
 
 # GLOBAL stash.

common/NQP/P6Objects.pm

@@ -16,4 +16,25 @@ class Mu {
     multi method ACCEPTS(Mu:U $self: $topic) {
         nqp::type_check($topic, self.WHAT)
     }
+    method defined() {
+        nqp::repr_defined(self)
+    }
+}
+
+class Capture is Mu {
+    has $.target is rw;
+}
+
+class Match is Mu {
+    has $.target;
+    has $.from;
+    has $.pos;
+
+    method chars() {
+        $!pos - $!from;
+    }
+
+    multi method Str() {
+        substr($!target.Str, $!from, $!pos - $!from)
+    }
 }

t/nqp/56-accessors.t

@@ -0,0 +1,15 @@
+# auto-generatored accessors & mutators
+#   but not lvalue as in Perl 6, just "fluent" mutator methods
+
+plan(2);
+
+class Foo3 { has $.bar is rw }
+
+my $foo := Foo3.new();
+
+# doesn't work yet; no viviself for attributes :(
+#ok(!$foo.bar());
+
+ok($foo.bar("baz") eq "baz");
+
+ok($foo.bar eq "baz");